Method for forming a graphic image web

ABSTRACT

Disclosed herein is a method of forming a graphic image having the appearance of three-dimensionality, the method comprising the steps of: providing a preformed lenticular film having a flat side and having a side with lenticules opposite the flat side; and printing an image on the flat side of the lenticular film using web fed printing to produce a graphic image web in which the perceptible image possesses photographically acceptable quality, wherein the image elements are printed on the lenticular film at an angle which corresponds to the pitch of the lenticules of the lenticular film.

CROSS REFERENCE TO RELATED APPLICATION

This is a continuation-in-part of U.S. Ser. No. 08/060,020, filed May10, 1993, now U.S. Pat. No. 5,285,238.

TECHNICAL FIELD

The present invention relates generally to methods for creating theillusion of three dimensionality of a graphic image in printed web form.

BACKGROUND OF THE INVENTION

It is known in the art to fabricate generally planar display deviceswhich include an image sheet and a lenticular lens sheet which, incombination, give the image and appearance of three dimensionality. Thelenticular lens sheet and the image sheet must be aligned properly toavoid a distorted image. The components have heretofore been in sheetform because the process of combining them is usually manual to ensurenecessary registration.

The illusion of three dimensionality requires the image originally bemade with a special three dimensional or stereoscopic camera,photographing the desired object from a plurality of angularly displacedpositions. Such a camera typically uses a photosensitive film disposedbehind a lenticular screen. The lenticular screen is positioned adjacentthe photosensitive film so the focal point of each lenticule generallycoincides with the front surface of the film. Thus, the image of theobject is focused into a narrow image band which is exposed in the film.As the camera is shifted to the next angular position, the lenticularscreen is also shifted slightly. A subsequent picture image of theobject from the new angular position is then exposed into a separateimage band in the film adjacent the preceding image band. Each time thecamera is moved to a new angular position, the object is photographedand the image is exposed in the film as a similar, narrow image bandadjacent the previously formed image band, until a series of image bandsrepresenting different views of the object is created. To avoid overlapof image bands, the lenticular screen is only moved a distance equal tothe width of a single lenticule as the camera is moved through its fullangular range. This collection of image bands, which is formed under asingle lenticule, may be called an image element. Each image element isapproximately the width of a single lenticule and includes all of thecondensed views of the object.

Cameras of this type are disclosed in Stockbridge et al., U.S. Pat. No.3,380,360, issued Apr. 30, 1968 and Bonnet, U.S. Pat. No. 2,508,487,issued May 23, 1950. Both of those patents disclose three dimensional orstereoscopic cameras used to photograph objects from numerous angularpositions where the photograph taken at each position is exposed on afilm as a linear image band.

Once the object is photographed from tile various positions, the filmmay be developed the same as any other photographic film, but theresulting image is a compilation of the numerous adjacent image bands.Each image band represents the object from a given angle, albeit in afocused or compressed form. This can provide the overall image with asomewhat distorted look to the naked human eye. However, when thedeveloped image is combined with a lenticular screen or sheet havinglenticules of approximately the same size and focal length as thelenticular sheet used to expose the film, the image becomes clear to thehuman eye as viewed through the screen.

The lenticular sheet must be placed over the image elements so the focalpoint of each lenticular lens coincides with the front surface of theimage sheet. The image will appear to be three-dimensional because theobserver is viewing the image through the lenticular sheet from aslightly different angle due to the lateral spacing between his eyes. Ineffect, this allows each eye to focus on a different image band,representing different views of the photographed object from separateangles, thereby giving the viewer the illusion of a three dimensionalimage.

In the past, the lenticules and image elements were relatively wide andeach lenticule had to be perfectly aligned over each image element toobtain a clearly, defined three dimensional image. It has been difficultto obtain precise alignment and impossible to mass produce threedimensional images efficiently and economically. Typically, thelenticular sheet has beer manually positioned over the image sheet andthen carefully adjusted to eliminate moire line or interference. This isa time consuming, inefficient and expensive task.

Further difficulties exist in mass producing three dimensional sheetsfor use in publications such as magazines due to the size of thelenticules and the consequent thickness of the lenticular lens sheet.However, larger lenticules have longer focal lengths and necessitate athicker lens overlay so the focal point of the lenticule isapproximately adjacent the image elements on the image sheet. This, ofcourse, leads to a relatively thick composite sheet which is notsuitable for magazines or other printed media that require a thinnersheet dimension. Making the sheet sufficiently than to be used inmagazines requires the lenticules to be extremely small thus making itmore difficult to form the lenticular lens sheet and properly align itwith the image sheet. The required precision has made the use ofefficient, high output machinery difficult.

It has long been desirable but unattainable to make both the image sheetand the lenticular lens sheet in continuous form and then combine themat a rapid pace with precise registry to produce a finished producthaving photographically acceptable quality. Standard printing methodscould then be used to reproduce the images in continuous form. Thoughtechniques have been developed for creating a lenticular lens incontinuous form, and certain methods and devices have also been used inan attempt to combine an image web with a continuous lenticular lens,none of these devices is able to produce a thin, flexible lenticularimage composite for economical use in the production of, for example,magazines while maintaining the precision necessary to produce qualityimages having the illusion of three dimensionality without interferencelines or distorted appearance.

In three patents to Conley, U.S. Pat. Nos. 4,420,502, issued Dec. 13,1983, 4,414,316, issued Nov. 8, 1983, and 4,420,527, issued Dec. 13,1983 an apparatus and method for making a composite sheet material aredisclosed. A transparent base web is directed onto the surface of afirst roll and advanced along an arcuate path around the first roll andthen through a narrow gap disposed between the first roll and a secondroll. Before the transparent base web passes between the first andsecond rolls, a flowable, uncured actinic radiation-curablethermosetting resin is directed onto the web behind the narrow gap. Thesecond roll includes grooves so that, as the resin covered web passesthrough the narrow gap and around the second roll, lenticular formationsare made in the flowable resin. Ultraviolet radiation is directedthrough the transparent basis web and into the flowable resin layerwhile it remains in contact with the second roll. Thus, the flowableresin is cured into a composite lenticular lens sheet.

Such a process can produce small, well defined lenticular lenses.However, the difficulty remains in properly joining such a lenticularlens with a corresponding image web in a manner that avoids distortionof the image. Typically, the lenticular lens will still need to be cutin sheets and then carefully aligned by hand with a corresponding imagesheet. It would be advantageous, and meet the long-felt need summarizedabove, if such a lenticular lens could be precisely aligned and combinedwith the corresponding images while the image sheet and the lenticularlens both remained in continuous form. This would greatly increase theefficiency and volume of the finished web resulting in a very economicalproduct.

Other patents disclose methods and devices for making lenticular lensproducts but none with the accuracy or precision that would allow thefinished product to be used in typical publications such as magazines.For instance, Jerothe et al., U.S. Pat. No. 3,264,164, issued Aug. 2,1966, discloses a device which makes a laminated, flexible fabric-likematerial having interesting characteristics of color and depth. However,precise accuracy is not necessary since one of the purposes of thepatented device is to produce images having a moire effect.Additionally, that approach uses colored lines and various coloredshapes placed at different depths between cumulative flexible sheets. Inthe Jerothe et al. device, a relatively thick sheet is used for theformation of the lenticular lens. The lenticular lens sheet is laminatedwith various films and the resulting laminate passes between a pressureroll and a gravure roll where surface ribs or lenticular lens type ribsare formed by pressing the relatively thick lens forming sheet againstthe gravure roll. That device, however, cannot be accurately controlledto make extremely small accurate lenses in alignment with the imagebands of an image web to yield photographically acceptable imagequality.

Leach, U.S. Pat. No. 3,565,733, issued Feb. 23, 1971 discloses anapparatus for making a composite web from paper web combined with meltedplastic. In Leach, a paper web, which can include an image, is passedbetween a pressure roll and a coating roll and then around a chilledembossing cylinder. A melted plastic is poured onto the coating rollwhich brings the melted plastic into contact with the paper web. Thiscombined paper web and melted plastic is immediately brought intocontact with the surface of the chilled embossing cylinder whichsolidifies the melted plastic leaving lenticular lens-type formations inplastic. A problem with the Leach apparatus is that it does not providefor the precision alignment of the lenticular lens formations with theimage elements on the image web. This prevents the constant replicationof high quality images having the appearance of three dimensionalitywithout distortion. Additionally, meltable plastic will not retain itsproper shape under the rigors of magazine use and shipping which cantend to place the lenticular lens formations under harsh conditions ofpressure and heat. Once the lenticular lenses degrade, the threedimensional effect is lost. See also U.S. Pat. No. 3,607,340 to Stroupeissued Sep. 21, 1971.

In Lemelson, U.S. Pat. No. 3,146,492, issued Sep. 1, 1964, an apparatusis disclosed which produces a multiple image sheet display on acontinuous basis. In Lemelson, an impressionable sheet is laminated witha plurality of sheets and then passed through a pair of rolls. One ofthe rolls is an embossing roll which creates lenticular formations in aface of the impressionable sheet. The apparatus is similar to thosementioned above in that it is difficult to form precision lenticules inthe solid web without which an image of photographically acceptablequality cannot be reliably and repeatedly reproduced. Additionally,there is no way for the machine to provide precise alignment of theimage elements with the lenticules.

The present invention addresses the foregoing drawbacks involved inmaking a precision lenticular lens image web having three dimensionalimage characteristics with photographic quality.

SUMMARY OF THE INVENTION

The invention provides a method of forming a graphic image having theappearance of three-dimensionality, the method comprising the steps ofproviding a preformed lenticular film having a flat side and having aside with lenticules opposite the flat side; and printing an image onthe flat side of the lenticular film using web fed printing to produce agraphic image web in which the perceptible image possessesphotographically acceptable quality, wherein the image elements areprinted on the lenticular film at an angle which corresponds to thepitch of the lenticules of the lenticular film.

One embodiment of the invention provides a method for forming a graphicimage web to produce the illusion of three dimensionality in a visuallyperceptible image, the method comprising the steps of defining an imagefield including an object to be viewed; imagewise exposing the objectonto a photographically sensitive element over a plurality of spatiallydisparate views through a lenticular lens having a prescribed opticalgeometry; developing the latent image on the photographically sensitiveelement; providing a lenticular lens web; and printing the developedimage on the lenticular lens web while the lenticular lens web istranslating in a machine direction to create the graphic image web withthe illusion of three dimensionality.

Other features and advantages of the invention will become apparent tothose of ordinary skill in the art upon review of the following detaileddescription, claims, and drawings.

BRIEF DESCRIPTION OF THE DRAWING

The invention will now be described with reference to the accompanyingdrawing, wherein like numerals denote like elements, and:

FIG. 1 is a schematic view of an object being exposed on photographicfilm through a lenticular sheet;

FIG. 2 is a front elevation view showing the formation of a graphicimage web by combining a precursor image web with a lenticular lens web;

FIG. 3 is a schematic perspective view showing the paths of travel ofthe precursor image web and the lenticular lens web as they arecombined;

FIG. 4 is a schematic side view of the relief cut roll which forms thelenticules in the lenticular lens web;

FIG. 5 is a schematic perspective view of a printing unit used in a weboffset press;

FIG. 6 is a schematic perspective view of a printing plate;

FIG. 7 is a side view of the graphic image web which includes theprecursor image web combined with the lenticular lens web;

FIG. 8 is a front elevation view showing formation of a graphic imageweb by combining a precursor image web with a lenticular coating;

FIGS. 9 and 10 are front elevation views showing formation of a graphicimage web by combining a precursor image web with a spot lenticularcoating; and

FIG. 11 is an enlarged view of a graphic image web formed with spotlenticulation.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention relates generally to methods for producing aprinted graphic image having the illusion of three dimensionality and,more specifically, to methods for doing so in which the components areweb or continuously fed. The methods of the present invention arecharacterized by their ability to achieve a finished graphic imagehaving photographically acceptable quality. While photographic qualityof a printed image is a complex function of many production variables,ranging from the quality of the optical equipment, grain size and speedof the film, the quality and type of the printing equipment and selectedprinting process, it can be reduced to a more subjective level. Qualitycan more conveniently be related to the ability of the observer todifferentiate the structure in the finished printed image; for example,the ability to distinguish qualitatively and quantitatively facialfeatures in portraits, (tree) limbs and foliage in panoramic vistas, andthe like. When considered in the context of the present invention andthe ensuing description, photographically acceptable quality thus refersto a benchmark measurement of clarity in the finished three-dimensionalview which is not materially, qualitatively distorted when compared tothe precursor image. This is unlike the prior art: methods capable ofadaptation to web-fed or coating operation cannot achieve acceptablequality, this is attainable only through labor intensive manualoperation using sheet components.

Referring now to the figures of the drawing, a method for forming agraphic image web will now be described. As shown generally in FIG. 1, athree dimensional or stereoscopic camera 10 is used to create an imagewhich, when developed, will give the illusion of three dimensionalitywhen combined with a lenticular lens web having the requisite opticalgeometry. An image field 12 includes an object 14 which is to bephotographed. A single object 14 is used for illustrative purposes, butthis should not be deemed as limiting image field 12 to a single object.For instance, numerous objects could be included in the image field evento the extent that image field 12 is filled with various objects aswould be the case when photographing certain scenery. Often, however,when creating stereoscopic images, it is desirable to have the object orobjects in a relatively narrow plane or lateral field of view to createan enhance three dimensional effect.

Stereoscopic camera 10 is mounted on a device (not shown) which allowsit to be moved through a plurality of spatially disparatepositions(shown in phantom)to obtain spatially distinct views of object14. Each of these spatially distinct views is exposed through alenticular film assembly 16 which includes a photographically sensitiveelement 18, such as photographic film, combined with a superimposedlenticular lens 20. As light, reflected from object 14, enters camera10, it passes through lenticular lens 20 and is focused into narrowcondensed bands exposing photosensitive element 18 along narrow imagebands.

In the preferred embodiment,lenticular lens 20 and photosensitiveelement 18 are relatively laterally movable. Photosensitive element 18is preferably mounted in a mechanism (not shown) which moves it inproportion to the movement of camera 10. Thus, as camera 10 moves fromone position to the next, photosensitive element 18 will move slightlyalong the length of lenticular lens 20(shown in phantom). By movingelement 18, the light reflected from object 14 at each adjacent cameraposition is focused by lenticular lens 20 into narrow bands adjacent thenarrow image bands exposed on photosensitive element 18 at the previouscamera position. Object 14 is thereby imagewise exposed at differentlocations along photosensitive element 18 with each exposure locationcorresponding to one of the spatially distinct views of the objectobtained at one of the camera positions.

More particularly, lenticular lens 20 includes a plurality of lenticules22 each having a given, preferably similar focal length depending on thesize and the curvature of the lenticules. When object 14 isphotographed, light reflected from object 14 enters camera 10 andstrikes lenticular lens 20. Each lenticule 22 focuses the light towardsits focal point. Preferably, photosensitive element 18 is disposedapproximately in line with the focal points of the plurality oflenticules 22. This insures that light striking each lenticule convergesinto a narrow band at photosensitive element 18, creating a plurality ofnarrow condensed image bands 24 where the light focused by eachlenticule exposes element 18.

Stereoscopic camera 10 is then moved to an adjacent location which givesa spatially disparate or distinct view of object 14. As camera 10 ismoved to the next position, lenticular lens 20 is moved slightly withrespect to photosensitive element 18 so that this view of object 14 willbe focused on element 18 by lenticules 22 along narrow image bands 24adjacent the prior image bands 24. Preferably, as camera 10 is movedthrough its full range of positions, lenticular lens 20 is moved withrespect to photosensitive element 18 over a distance approximately equalthe width of one lenticule 22. This will ensure that the image bands 24created at each position of camera 10 will adequately expose the entiresurface of photosensitive element 18 while preventing overlap of theimage bands 24 formed under one lenticule with those formed under theadjacent lenticule.

When photosensitive element 18 is completely exposed, it will include aplurality of image elements 26. Each image element 26 is ofapproximately the same width as the width of each lenticule and includesa plurality of image bands 24 representing the various spatiallydisparate views of object 14 taken from and corresponding to thedifferent positions of camera 10. In the most preferred embodiment,camera 10 is continuously moved through its range of positions with itsshutter held open. Simultaneously, lenticular lens 20 is continuouslymoved laterally with respect to photosensitive element 18 in an amountgenerally equal to the width of one lenticule. This provides foruninterrupted imagewise exposure of object 14 onto photosensitiveelement 18 so that there are no visually discernable breaks or gapsbetween image bands 24. Instead, image elements 26 each comprise thefocused composite of the spatially disparate views obtained when camera10 is moved through its range of motion while object 14 is continuouslyexposed along element 18.

If camera 10 is moved through a substantial range of positions, it ispreferably moved along an arcuate path so that the distance betweenobject 14 and camera 10 remains constant. However, if the spatiallydisparate views of object 14 are created with minimal motion of camera10, then camera 10 can be moved along a straight line (i.e. a chord) asdepicted in FIG. 1. This will not substantially affect the quality ofthe exposed latent three dimensional image on photosensitive element 18due to the slight difference between arc and chord length.

Following exposure of image elements 26 on photosensitive element 18,the latent image may be developed by normal methods used in developingphotographic film or other light sensitive emulsions. The developedimage is then printed on a web, referred to herein as a precursor imageweb, and replicated along the longitudinal length of the web usingconventional printing techniques. The web may be made of a variety ofmaterials, including, for example, paper stock typically used formagazines. Image elements 26 are aligned generally longitudinally withthe web, or in other words, are aligned generally on the machinedirection. As discussed below, however, it is preferred that the imageelements are disposed at a slight angle to the true machine direction.

To create the illusion of three dimensionality, the precursor image webmust be optically combined with a lenticular lens. The lenticules of thelenticular lens are aligned with the image elements 26 so that a personviewing the images on the precursor image web will perceive them asbeing three dimensional. Forming the lenticular lens and aligning itwith image elements 26 of the precursor image web is a precisionoperation performed by a web apparatus 30, shown generally in FIG. 2 and3.

Web apparatus 30 is used to combine a precursor image web 34, includingimage elements 26, with a congruent lenticular lens(which may be leftblank, printed with ordinary two dimensional images, or printed withimage elements) web 36. Precursor image web 34 includes a back side 38and a three dimensional or 3-D printed side 40 which is placed inregistry with lenticular lens web 36.

In the preferred embodiment, shown generally in FIG. 2, a printed roll42 of precursor image 34 is mounted in web apparatus 30. Precursor imageweb 34 translates through a tensioner assembly 44 and then through ahood 46 where an adhesive 48, such as Morton International Blend 2359pressure sensitive adhesive, is applied. Precursor image web 34 alsomoves through an optional lateral registration assembly 50 which slavesprecursor image web 34 to lenticular lens web 36 so that they are inproper lateral or transverse registry when combined into graphic imageweb 32. Registration assembly 50 is optional because it has been foundthat in some applications lateral registration is not required.

Once precursor image web 34 and lenticular lens web 36 are properlyaligned, with or without the assistance of registration assembly 50, thewebs are pressed together between a base roll 52 and a biased pressureroll 54. Pressing web 34 and web 36 against base roll 52 allows adhesive48 to convert the two webs into single graphic image web 32.

In the preferred method for forming lenticular lens web 36, a flexibleweb 56 is combined with a flowable resin 58. Flowable resin 58 is formedinto a plurality of lenticules 60 and cured so that lenticules 60maintain their shape (see FIG. 4). Flexible web 56 preferably comprisesa transparent plastic material such as polyester, although otherflexible relatively transparent materials could be used. A plastic roll62 of flexible web 56 is mounted in web apparatus 30 and supplies theflexible web 56 for combination with resin 58. When web apparatus 30 isoperating, web 56 moves through a tensioner assembly 64, around aplurality of guide rolls 68, and into a lenticule forming station 70(discussed below). After moving through forming station 70, flexible web56 moves around additional guide rolls 72 and then into contact withprecursor image web 34 at base roll 52.

As mentioned above, it is important that precursor image web 34 andlenticular lens web 36 are optically aligned when combined between baseroll 52 and biased pressure roll 54. Preferably, lenticules 60 haveapproximately the same cross-sectional dimensions and focal lengths aslenticules of lenticular film assembly 16. This allows each lenticule 60to be linearly aligned with a single image element 26 on the precursorimage web 34.

If lenticules 60 are large in cross-section, a better three-dimensionaleffect is achieved by laterally aligning a single lenticule directlyover each image element 26. However, as lenticules 60 and thecorresponding image elements 26 are made narrower, it has beendetermined in accordance with the present invention that the need forprecise lateral alignment is reduced. A desired three dimensional effectis produced by laminating precursor image web 34 to lenticular lens web36 so that the lenticules 60 are linearly aligned with image elements26. Proper linear alignment prevents distortion due to the crisscrossingof lenticules 60 with image elements 26.

In the preferred embodiment, the number of the lenticules 60 area is atleast 100 per inch. At this density of lenticules, a desired illusion ofthree dimensionality may be achieved without the use of lateralregistration assembly 50. In the most preferred embodiment, the densityof the lenticules 60 is at least 300 per inch. This eliminates the needfor registration assembly 50 and also provides a short lenticule focallength to facilitate an extremely thin graphic image web 32.

In some cases, it may be desirable to alter the orientation oflenticules 60 with respect to image elements 26 to optically align themin a manner which produces moire patterns. However, it is generallydesirable to avoid any formation of moire patterns.

When lateral registration is required, registration assembly 50preferably comprises an ultrasonic guidance system. Ultrasonic guidancesystem 73 uses a pair of ultrasonic sensors 74 and 74', each of whichproduce an ultrasonic beam which tracks the edge of the web it ismonitoring. Sensor 74 monitors an edge of precursor image web 34 whilesensor 74' monitors the edge of flexible web 56. The frequency of theultrasonic beam changes as it passes through different materials. Thus,the frequency of the beam passing through a web is different from thefrequency of the beam as it passes through atmosphere. The ultrasonicbeam either passes completely through the atmosphere, completely throughthe web, or partially through each, thereby allowing sensors 74 and 74'to read precisely the lateral position of each web. The preferredguidance system is the Model A9H manufactured by FIFE Corporation.

Since it has been determined that flexible web 56 tends to retain itslateral position, it is preferable to adjust the lateral position ofprecursor image web 34 to laterally align lenticular lens web 36 andprecursor image web 34 prior to laminating them into single graphicimage web 32. To obtain this lateral registry, the sensors, 74 and 74',supply an output signal to a controller which, in turn, provides outputsignals which control a guide roller assembly 76. Guide roller assembly76 is preferably hydraulically controlled to adjust the position ofprecursor image web 34 in the lateral direction. Such guide rollassemblies are commonly known and used in the printing industry.

Other types of guidance systems may also be used to provide preciselateral registry of the webs. For example, a laser guidance system whichuses a laser beam to track the edge of each web may be used.Additionally, a stylus guidance system could be used. In such a stylusguidance system, a stylus cooperates with a sensor to track a ridge or agroove disposed along the edge of a web, preferably the lenticule lensweb. It is important to note that with any of these guidance systems,the groove, ridge or edge being tracked must be straight so that thewebs can be accurately registered and combined.

In the embodiment illustrated, the precursor image web 34 is slaved tothe lenticular lens web 36. However, registration assembly 50 could beconnected to slave the lenticular lens web 36 to precursor image web 34.In either case, the lateral registration of webs 34 and 36 occurs duringthe translation of each web prior to laminating webs 34 and 36 to formgraphic image web 32. This process allows efficient production ofcommercially viable lengths of graphic image web 32 when precise lateralregistration is required.

To facilitate efficient production of graphic image web 32, lenticularlens web 36 is created during the translation of flexible web 56 throughweb apparatus 30. As shown generally in FIG. 5, lenticule formingstation 70 comprises a coating roll 77 around which flexible web 56translates in an arcuate path. Flexible web 56 includes an inner surface78 which is later adhered to the 3-D printed side (i.e. the image side)40 of precursor image web 34. Flexible web 56 also includes a receivingsurface 80 on which the flowable, curable resin is deposited. Flowableresin 58 may be applied directly to receiving surface 80, but in apreferred embodiment, resin 58 is applied to a coating roll 77 whichthen rotates into cooperation with receiving surface 80 as showngenerally in FIG. 4. Flowable resin 58 is applied by an applicator 82which creates a reservoir 84 of flowable resin 58 on the surface ofcoating roll 77. However, other methods of applying flowable resin, suchas by spraying it onto coating roll 77, may be used without departingfrom the scope of the invention.

As flexible web 56 moves into lenticule forming station 70 it is routedaround a tension nip roller 86 and then into contact with coating roll77 in close proximity and on the downstream side of applicator 82. Thus,reservoir 84 is held between nip roller 86 and coating roll 77 so thatreceiving surface 80 of flexible web 56 is uniformly wetted withflowable resin 58. once surface 80 is wetted, the desired opticalsurface pattern is formed in the flowable resin 58 on flexible web 56.

Coating roll 77 is relief-cut in a predefined optical surface pattern.This optical surface pattern is preferably a recessed pattern oflenticules which imparts a convex lenticular pattern to the flowableresin 58. This desired pattern is maintained as flexible web 56 movesthrough lenticule forming station 70 and is cured prior to any levelingwhich would materially impair the desired lenticular pattern. Thelenticular pattern is maintained by holding flexible web 56 in contactwith coating roll 77 until it moves into proximity with a tension roller88 disposed downstream of coating roll 77. In the preferred embodiment,flowable resin 58 is a UV curable resin and is cured before flexible web56 moves out of contact with coating roll 77. A plurality of UVradiators 90 are disposed about coating roll 77 in such a manner thatthe UV rays are directed through the base of transparent flexible web 56and into resin 58 while it is maintained in the desired lenticularpattern against relief cut coating roll 77.

The relief cut pattern extends in an arcuate path around thecircumference of coating roll 77. Preferably, the pattern is a screwPattern wherein one continuous relief cut groove, corresponding to thedesired physical shape of each lenticule, continually wraps around thecoating roll 77 similar to the thread of a screw. Thus, the relief cutgroove has a given pitch angle dependent on the size of the groove andthe diameter of coating roll 77. Such a continuous groove requires acoating roll 77 of sufficient size so that the pitch of the groove isnegligible. This ensures that the lenticular pattern formed in flowableresin 58 is nearly linearly aligned with the machine direction oflenticular lens web 36.

Roll 77 is relief cut to correspond to the desired number and thedesired shape of lenticules 60 both of which can vary substantiallydepending on various image web manufacturing parameters and the desiredthree dimensional effect. To obtain a thin image web 32, it is desirableto have 100 or more lenticules per inch so that the convex lenticule hasa short focal length and the thickness of lenticular lens web 36 isminimized. As mentioned above, a higher density of lenticules reduces oreven eliminates the need for precision lateral registration.

The preferred shape of lenticules 60 is of a half cylinder splitlongitudinally, as shown generally in FIG. 7. However, the shape of thelenticule can be adjusted to facilitate shorter focal lengths withouthaving as great a multiplicity of lenticules per inch. Each lenticulecan be formed with greater curvature at its apex than throughout theremainder of the lenticule to provide a shorter focal length with abroader overall lenticule cross section. An example of such a lenticuleis one having a hyperbolic cross section.

To obtain optical alignment for the greatest three dimensional effect,the images on precursor image web 34 are tilted slightly with respect tothe machine direction of web 34. The tilt of the images corresponds tothe pitch of the lenticules 60 so that the image elements 26 arelinearly aligned with lenticules 60. In the preferred embodiment, thetilted images are created on precursor image web 34 with a web offsetpress, although other types of presses such as gravure or flexographicpresses can also be used.

A web offset press uses a printing unit 92 shown schematically in FIG.5. Ink is applied to an image carrier, such as a plate 94, which wrapsaround a plating cylinder 96. Plate 94 is etched with the desired imageand transfers the ink held by the etched image to a blanket cylinder 98which, in turn, transfers the image to precursor image web 34. Imagesmay be printed on both sides of the precursor image web 34, as shown inFIG. 5. Usually, a series of printing units 92 is required since only asingle color will be applied at each printing unit 92.

To obtain optical alignment, the images are printed on precursor imageweb 34 at an angle which matches the pitch angle of the screw threads oncoating roll 77. This is preferably accomplished by one of two differentmethods. According to one method, plate cylinder 96 is cocked or rotatedso that it is no longer perpendicular to the machine direction ofprecursor image web 34. The angle of rotation from perpendicularapproximately matches the pitch angle imparted to lenticules 60.Accordingly, the cocked plate cylinder 96 transfers the image to blanketcylinder 98 at the same angle so that the image elements 26 andlenticules 60 will be linearly aligned when graphic image web 34 andlenticular lens web 36 are combined.

According to the second method, the images are etched on plate 94 at thedesired pitch angle as shown in FIG. 6. Plate 94 includes an axis 100which is aligned with the machine direction of precursor image web 34.However, when an image 102 is etched in plate 94, it is oriented at anangle with respect to axis 100. This angle corresponds approximatelywith the pitch angle of the recessed screw threads on coating roll 77.Thus, like before, as precursor image web 34 is laminated to lenticularlens web 36, lenticules 60 will be linearly aligned with image elements26.

Following the curing of flowable resin 58 and the formation oflenticular lens web 36, lenticular lens web 36 moves around guide rolls72 and into contact with precursor image web 34 where it is adhered toprecursor image web 34 to form graphic image web 32 as described above.As shown generally in FIG. 7, graphic image web 32 typically comprises alayer of printing paper 106 on which are printed the image elements 26creating a printing layer 108. A layer of relatively transparent:adhesive 48 is disposed on printing layer 108 and secures inner surfaceof flexible web 56 to precursor image web 34 (which includes paper 106and printing layer 108). A pre-defined topography 110 is formed fromcurable resin 58 and disposed on receiving surface 80 of flexible web56. In the preferred embodiment, the predefined topography 110 is formedin the pattern of lenticules 60 having the desired configuration andoptical qualities so that when image elements 26 are viewed throughlenticules 60 and flexible web 56, the illusion of three dimensionalityis created. In this respect, it is desirable that each lenticule be ofgenerally the same width as each image element 26 and that eachlenticule 60 has a focal length which coincides with its distance fromprinting layer 108.

Numerous materials may be used to create the various layers which arecombined to form graphic image web 32. For example, flexible web 56 andlenticules 60 made be made from polycarbonate and laminated to apolycarbonate precursor image web 34. In another situation, it may beadvantageous to use Tyvek, a material manufactured by the DuPontCompany, as the precursor image web. A wide variety of materials,including synthetics and nonsynthetics, those with woven or nonwovenfibers, and those with oriented or nonoriented fibers may be used toform one or more of the precursor image web 34, flexible image web 56,or lenticules 60.

Referring now to FIG. 8, an alternative embodiment of the invention inwhich the lenticular lens is formed by applying a coating to theprecursor image web will now, be described. It should be understood thatthe prior art has concentrated mainly on formation of the lenticularlens without corresponding concern for the optical alignment of thelenticular lens with the base film or precursor image web to which it isjoined. In an effort to minimize distortion which occurs when a basefilm or precursor image web becomes skewed or misoriented in its path oftravel, the invention incorporates the combination of a speciallyprocessed precursor image web with a curable lenticular lens coating.

In accordance with the invention, precursor image web 34 is formed andprocessed as described above wherein the image elements are slightlytilted with respect to machine direction of web 34. Web 34 passesthrough a tensioning device 112 and around a coating roll 114 where afluid coating 116 is directly applied from a source 118. A fountainblade 120 is utilized to wipe off excess coating 116 from roll 114. Web34 then passes under a forming member 122, such as a knife or rotatingbar, relief cut with the desired lenticular pattern having a pitchcorresponding to the tilt angle of the image elements printed on web 34as before described. After the lenticular coating has been formed, web34 travels past an ultraviolet lamp, or is otherwise cured, such as bychemical curing,drying, infrared or ultrasonic beam. Composite graphicimage web 32 is thus continuously formed such that the lenticules incoating 116 are in registration with the tilted image elements inprecursor image web 34.

It should be appreciated that precursor image web 34 may be coated witha lenticular lens in a variety of modes including direct gravure andflexographic and in combination with various laminations.

Another particular form of the invention contemplates improved spot orselective lenticulation on the precursor image web. In one sucharrangement shown in FIG. 9, a rotating coating or anilox roll 126transfers resin or coating 128 from a reservoir 130 or manifold 132 tothe segments 134 of a plate cylinder 136 which is relief cut with thelenticular pattern again matching the angular orientation of the imageelements on the precursor image web 34. Rotation of plate cylinder 136thus transfers segmented or spot lenticulation to precursor image web 34routed between a displaceable backup cylinder 138 and plate cylinder136. After the lenticular coating 128 has been deposited on selectedareas of the web, a curing source 140, such as an ultraviolet radiatoror the like, is used to cure lenticular coating. Once again a doctorblade 142 is used to remove excess coating 128 from roll 126.

FIG. 10 shows another embodiment wherein coating 144 from a manifold 146governed by a timing control 146a is directly applied to a relief cutgravure cylinder 136a before spot transfer to web 32.

Segments 134 on plate cylinder 136 are constructed of urethane, rubber,copper or stainless steel and are interchangeable to provide varioustapered effects of the lenticular coating. Any number of coatingstations, or decks, with various sized segments 134 may be utilized toproduce web 32 so as to build up a layered spot lenticulation such asshown in FIG. 11 wherein a three-layered coating 148 results in a spotlenticulation of generally frustro-conical or trapezoidal cross sectionhaving downwardly sloping sides 150 to yield a certain effect.

In one alternative embodiment of the invention, the offset web press ofFIG. 5 is used to print directly on a web of lenticular film. Moreparticularly the offset web press is used to print onto a lenticularfilm having lenticules preformed thereon. The lenticular film ismanufactured of a transparent material such as polyester, vinyl, orpolycarbonate, upon which the precursor image is reverse printed on theflat or non-lenticular side. The transparent material is preferableextruded. The perceptible image is viewed from the lenticular side.

The same absolute registration demands as described earlier in theinvention apply to this embodiment; such as tilt of the image, printingplates or cylinder, to the angle or pitch of the lenticules, which canbe either continuous screw pitch or "step-and-repeat".

This form of printed material would greatly reduce the overall thicknessof the finished product, thus enabling it to be used in a greater rangeof applications. The finished product has application in a wide varietyof products. For example, the finished product can be used in textbooks,such as medical textbooks, without an undesirably high thickness. Thefinished product has automotive applications, e.g. to provide anillusion of depth in an instrument cluster, in dashboards, or in otherparts of an automobile interior. The finished product has application inpackaging materials (e.g. packages that are displayed on store shelves).The finished product has application in magazine covers. Otherapplications will be apparent to one of ordinary skill in the art.

The printing could be accomplished (but not necessarily restricted to)with any printing method such as web offset, flexographic, gravure,stochastic, or electronic deposition, the latter being a form ofprinting presently being used for high speed labeling, colorproductions, etc. Some forms of electronic deposition include laserprinting, videojet, ink jet. Regardless of the method employed, a highprecision press should be employed. In the preferred embodiment, a weboffset method is employed using a high precision press such as a HarrisM-1000. An example of a high precision flexographic press is a StevensGraphics 2000.

After printing of an image on the lenticular web, an opaque coating isused to cover the image printed on the lenticular web. The opaquecoating has sufficient density to permit printing thereon without theprinting on the coating being visible on the side of the lenticular filmhaving the lenticules thereon. A white coating can be used to cover theimage that is printed on the lenticular web, and a normal 2-D image canbe printed on the white coating. This is useful for magazine covershaving a 3-D outside cover and a 2-D inside cover. Alternatively, a 3-Dimage can be formed on the white coating by methods described above.

The locations of the image web relative to machine configuration wouldbe similar to descriptions presented earlier in the patent application.

The lenticular web is pre-manufactured to the correct pitch andthickness to provide the viewer with the illusion of 3-D. Themanufacturing process of the lenticular web is through extrusion,co-extrusion, casting, embossing, or coating so as to provide a suitableplatform for reverse printing thereon for a 3-D image web.

This process provides significant cost savings. This process eliminatesthe printing of the precursor web, the lamination process and theaforementioned casting or coating process.

Manufacture of the cylinder used in the pre-forming (casting operation)of the lenticular web which is to be printed upon is accomplishedthrough either the continuous screw pitch configuration or through aprocess of step-and-repeat, whereby a preformed tool is plunged into themedia constituting the roll surface, then retracting and moved to thenext position as determined by the lenticular screen; i.e., 135 linesper inch or 200 lines per inch. It is imperative that the movement orindexing of the tool conform exactly to the requirements of the printedcommunication to be viewed through it. The term "tool" used in the lastsentence can be used to describe a solid device such as diamond, orcarbide or other material removing device such as laser or EDM.

It will be understood that the foregoing description is of a preferredexemplary embodiment of this invention, and that the invention is notlimited to the specific form shown. For example, the lenticules may beof different shape or size, different types of curable resin may beused, and the arrangement of various components in web apparatus may bechanged. These and other modifications may be made in the design andarrangement of the elements without departing from the scope of theinvention as expressed in the appended claims.

What is claimed is:
 1. A method of forming a graphic image having theappearance of three-dimensionality, said method comprising the stepsof:providing a preformed lenticular film having a flat side and having aside with lenticules opposite the flat side; and printing an image onsaid flat side of said lenticular film using web fed printing to producea graphic image web in which the perceptible image possessesphotographically acceptable quality, wherein said image elements areprinted on said lenticular film at an angle which corresponds to thepitch of said lenticules of said lenticular film.
 2. The method of claim1 wherein said lenticular film is manufactured of a material selectedfrom the group consisting of polyester, vinyl, and polycarbonate.
 3. Themethod of claim 1 wherein said lenticular film is an extruded polyesterweb.
 4. The method of claim 1 and further comprising the step ofapplying an opaque coating over said printed image, said opaque coatingbeing of sufficient density to permit printing thereon without theprinting on the coating being visible on the side of said lenticularfilm having said lenticules thereon.
 5. The method of claim 4 whereinsaid opaque coating is white.
 6. The method of claim 1 wherein saidimage is printed on said lenticular film by web offset printing.
 7. Themethod of claim 1 wherein said image is printed on said lenticular filmby flexographic printing.
 8. The method of claim 1 wherein said image isprinted on said lenticular film by a printing method selected from thegroup consisting of web offset, flexographic, gravure, stochastic, andelectronic deposition printing.
 9. The method of claim 1 wherein saidlenticules on said lenticular film are of sufficient density to producesaid graphic image web in which the perceptible image possessesphotographically acceptable quality.
 10. A method for forming a graphicimage web to produce the illusion of three dimensionality in a visuallyperceptible image, said method comprising the steps of:defining an imagefield including an object to be viewed; imagewise exposing said objectonto a photographically sensitive element over a plurality of spatiallydisparate views through a lenticular lens having a prescribed opticalgeometry; developing the latent image on said photographically sensitiveelement; providing a lenticular lens web; and printing the developedimage on the lenticular lens web while said lenticular lens web istranslating in a machine direction to create said graphic image web withthe illusion of three dimensionality.
 11. The method of claim 10 whereinsaid step of imagewise exposing said object through said lenticular lensover a plurality of spatially disparate views creates a plurality ofimage elements on said photographically sensitive member, each imageelement being defines by a plurality of condensed image bands, eachimage band representing a particular spatially disparate view, andfurther wherein said plurality of image elements are developed on saidphotographically sensitive member and printed onto said lenticular lensweb.
 12. The method of claim 10 wherein said developed image is printedon the lenticular lens web with sufficiently high precision to createsaid graphic image web with graphic information of photographicallyacceptable quality.
 13. The method of claim 11 wherein the step ofprinting the developed image is replicated along the length of saidlenticular web.